1. Field of the Invention
The present invention relates to an oil supplying apparatus for a horizontal type rotary compressor, and in particular to an oil supplying apparatus for a horizontal type rotary compressor, usually used in a freezing and/or a refrigerating machine, capable of assuming substantial oil supply to the compressor and preventing oil leakage to the outside thereof, thereby enhancing the oil supply efficiency of the compressor.
2. Description of the Conventional Art
Referring to FIG. 1 and FIG. 2, a conventional oil supplying apparatus of a horizontal type rotary compressor is shown.
As shown therein, an outer circumferential surface of a hollow cylindrical stator 11 is fixedly disposed at a predetermined portion inside the cylindrical body 10. A rotor 12 rotatably electrically cooperating with the stator 11 is disposed inside the stator 11. Here, there is formed a gap between the inner circumferential surface of the stator 11 and the outer circumferential surface of the rotor 12. A shaft 13 is fixedly integrally inserted into the rotor 12. An oil path 14 having a predetermined depth and diameter is formed inside the shaft 13. A plurality of oil supplying openings 14' are formed at the circumferential surface of the oil path 14.
Meanwhile, a shaft 13 passes through a main bearing 15. A sub-bearing 16 is rotatably inserted onto the shaft 13 while maintaining a predetermined distance with the main bearing 15. An eccentric shaft 17 integrally formed with the shaft 13 and having a different center of rotation against the shaft 13 is disposed between the main bearing 15 and the sub-bearing 16. A roller 18 having a predetermined thickness is evenly formed around the outer circumferential surface of the eccentric shaft 17. An internal circumferential surface of the cylinder 19 is formed outside the roller 18. Here, the outer circumferential surface of the roller 18 travels along the internal circumferential surface of the cylinder 19. The center of the cylinder 19 is eccentrically formed against the center of rotation of the roller 18. Meanwhile, the outer circumferential surface of the cylinder 19 is fixedly affixed to the inner circumferential surface of the body 10 while maintaining a predetermined air gap therebetween. A bolt 20 is disposed in order to secure the main bearing 15, the sub-bearing 16 and the cylinder 19. Here, since the internal center of the cylinder 19 corresponds to the center of the shaft 13 and the rotation center of the eccentric crank shaft 17 is eccentrically formed against the shaft 13, as the shaft 13 rotates, the roller 18 eccentrically travels along the inner circumferential surface of the cylinder 19. Accordingly, as the roller 18 rotates, a predetermined space is generated inside the cylinder 19. Meanwhile, a vane groove 21 is formed at a predetermined portion of the cylinder 19. A vane 22 is slidably inserted into the vane groove 21. Here, when the eccentric crank shaft 17 is positioned at the top dead point inside the cylinder 19, there is defined a suction chamber 23 at right space which is defined by the outer circumference of the roller 18 and the vane 22 and there is defined a compression chamber 24 at the opposite portion thereof. The volume of both the suction chamber 23 and the compression chamber 24 vary as the roller 18 rotates along the inner circumferential surface of the cylinder 19. Meanwhile, a spring 25 is disposed under the vane 22 inside the vane groove 21 in order to elastically support the vane 22.
Meanwhile, an injection opening 26 is formed in the suction chamber 23 in order to guide the refrigerant therethrough. An exhaust opening 27 is formed in the compression chamber 23 in order to guide the compressed refrigerant therethrough. A reed valve (not shown) is disposed at the entrance portion of the exhaust opening 27, which is forcibly opened by the compressed refrigerant. Here, the outer circumferential surface of the cylinder 19 is affixed to the inner circumferential surface of the body 10. Here, the exhaust opening 27 is extended to a first refrigerant chamber G1 through the main bearing 15. One end of an oil supplying pipe 29 is connected to a predetermined portion of the wall of the vane groove 21. Here, a liquid diode 28 is disposed at one end thereof and the other end thereof is connected to an oil path 14. An oil opening 31 having a liquid diode 30 at one end thereof is formed at a predetermined portion of the wall of the vane groove 21. The oil 60 provided at the bottom portion of the body 10 is supplied to the vane groove 21 through the oil opening 31.
In the drawings, reference numeral 40 denotes a power supplying section in order to supply power to the motor consisting of the stator 11 and the rotor 12. Reference numeral 50 denotes an exhaust pipe for exhausting the compressed refrigerant therethrough. Reference numeral 60 denotes oil.
The operation of the conventional horizontal type rotary compressor will now be explained.
To begin with, oil 60 is provided at the bottom portion of the body 10 at a predetermined level. When the power is supplied to the stator 11, the rotor 12 rotates in cooperation with the stator 11. As the rotor 12 rotates, the eccentric crank shaft 17 rotates in cooperation with the stator 11. When the eccentric crank shaft 17 is positioned at the bottom dead point inside the cylinder 19, the outer circumferential surface of the roller 18 is in slide contact with the top portion of the vane 22. At this time, the spring 25 is compressed thereby. As in the aforementioned state, the roller 18 rotates by about 24.degree. in counterclockwise direction, the pressure in the suction chamber 23 is lowered and at the same time the refrigerant is sucked through the injection opening 26. When the roller 18 is placed at the top dead point, the suction chamber 23 is filled with the refrigerant. When the roller 18 is positioned at the bottom dead point, the upper portion of the roller 18 is filled with the refrigerant in maximum. At this time, when the roller 18 begins to rotate in counterclockwise direction, the refrigerant in the compression chamber 24 is compressed by the rotation force of the roller 18. When the refrigerant in the compression chamber 24 is compressed at a predetermined level, the reed valve(not shown) is forcibly opened and the refrigerant is exhausted to the first refrigerant chamber G1 therethrough.
Meanwhile, much friction heat is generated between the outer circumferential surface of the shaft 13 and the inner circumferential surface of the main bearing 15 and the sub-bearing 16. In an attempt to reduce the friction resistance therebetween, the oil 60 is supplied thereto.
The oil operation will now be explained.
To begin with, oil 60 is supplied at the bottom portion inside the body 10. Here, the oil 60 freely moves between the first refrigerant chamber G1 and the second refrigerant chamber G2 because the outer circumferential surface of the cylinder 19 is not sealingly affixed to the inner circumferential surface of the body. The oil 60 flows to the vane groove 21 through the oil path 31. Meanwhile, as the roller 18 rotates eccentrically, the vane 22 moves vertically along the vane groove 21. When the eccentric crank shaft 17 is placed at the bottom dead point, the vane 22 is placed at the lowest portion and the oil 60 in the vane groove 21 is compressed and forcibly enters the oil supplying pipe 29. Meanwhile, the eccentric crank shaft 17 is placed at the top dead point, the vane is placed at the maximum upper portion and the oil 60 is sucked from the oil path 31. Here, the liquid diodes 28 and 30 are each disposed at the oil supplying pipe 29 and the oil opening 31 in order to prevent the backward flowing of the oil 60.
However, when the volume of the vane groove 21 increases, that is, the eccentric crank shaft 17 rotates toward the top dead point, a backward flow of the oil might occur at the liquid diode 28 and on the contrary, when the volume of the vane groove decreases, that is, the eccentric crank shaft 17 rotates toward the bottom dead point, backward flowing of oil 60 might occur at the liquid diode 30, thereby causing insufficient oil supply whereby friction induced heat-damage might occur.